Impregnated sleeving



March 17, 1936. w. H. PEARCE 2,034,352

IMPREGNATED SLEEVINCT Filed Feb. 8, 1934 Will/am Pearce Patented Mar. 17, 1936 UNITED, STATES PATENT OFFICEJ 2,034,352 a it IMPREGNATED sLEEvING William H. Pearce, Cincinnati, Ohio Application February a, 1934, Serial No. 710,341

30mi s. (01. 91-63) The present invention-relates to an improved impregnated sleeving product anda novelmethod of making the same. The invention further I relates to products .known as varnished or saturated sleeving and varnished tubing which are prepared from the impregnated-sleeving of the invention and has for an object the provision of varnished sleeving and tubing that are exceptionally flexible and which are furthermore very elastic under bending, twisting I and compressive strain and which .possess a heretofore unattainedelasticity under stretching and longitudinal compressive strains.

A further object of the invention is to provide a simple and eflicient method of preparing hollow braided fabric tubing for impregnation with a stiffening agent whereby the foregoing mentioned advantages may be attained in the products prepared from the impregnated tubing.

A further object of the invention is to provide amethod of mounting untreated tubular braided fabric on a mandrel or rod to insure rapid and easy removal of the tubing after impregnation without damage thereto;

Another object is toprovide a fabric tubing that is impregnated while under longitudinal compressive strain and which, upon coating by known methods with ordinary insulating varnishes provides a substantially crackproof varnished tubing.

These and other objects are attained by the means and method herein described anddisclosed in the accompanying drawing, in which:

Fig. 1 is a view,,;part broken away, of a piece of untreatedtubing in position upon a mandrel rod prepar'atory to impregnation.

Fig. 2 is a somewhat diagrammatic and enlarged longitudinal section of the tubular braided fabric used. 1 V

Fig. 3 is a similar diagrammatic and enlarged longitudinal section of the tubing as compressed on the mandrel for impregnation.

Fig. 4 is a similar diagrammatic and enlarged section showing the position of the strands in the finished sleeving and varnished tubing pre-' pared from the impregnated tubing of the inven- Fig. 5 is a cross sectional view of the varnished tubing. r

. Heretofore the product known generally as impregnated sleeving from which were made these ca'lled varnished sleeving and varnished tubing which diflic'ulties have oftentimes resulted in finished products which cracked when bent or twisted, thereby'rupturing the applied insulating body. Among other efforts to overcome these 7 difliculties and improve the flexibility and resilience of the product, considerable attention has been directed to the product of special varnishes of great flexibility and elasticity. Practically none of the ultimateproducts have been all that could be desired prior to the present invention. The present invention then, at once provides a better and more workable article of manufacture and vastly simplifies the production thereof by insuring easy removal'of the tubing from the mandrel after impregnation which is the initial step in the manufacture of this class of articles.

For the manu acture of 'the impregnated tubing a tubular braided sleeve of any suitable type. such as braided tubing 6, is used and this is cut into lengths considerably in excess of the length 0f finished product to be made. The tubular braid may be of any suitable yarn size on any style of braider. If desired the braid may be colored and shrunk after an optional initial cleaning and air drying to lay the fibers of the yarn strands. By way of example and not of limitation, a manufacturer employing thirty-six inch (36") mandrels for maufacturing thirty-six inch (36") lengths of impregnated sleeving would cut the braided tubular sleeving into lengths of approximately fifty inches (50) and each of these lengths of tubular sleeving would have inserted in them one of the mandrel rods. The rods serve to'hold the tubes open so that the inner walls of the sleevingcan not collapse. The entire length of sleeving is first compressed longitudie nally into a space of thirty-six inches (36") and,

allowing a small amount of the sleeving .to extend beyond the ends of the mandrel, the sleeving is fixed to the mandrel closely adjacent the ends" thereof by anysuitable means such as tying, glueing, or clamping. The excess length of sleeving disposed between the fixed portions is now distributed evenly overthe length of the mandrel by merely rubbing it lightly over or between any kind of surfaces, for example, by drawing the mandrel and sleeving through the fingers. This leaves a'slack in the braid which makes thebraid tend to stand away from the mandrel rod.' The" threads of the braidthus secured on the mandrel are not-impregnated wizh any desired sizing medium which may be a starch so1uti0n, suitable shellac or varnish solution or a glue solution. The application may be by spray, brush or dipping or otherwise flowing the sizing material on in all brittle, and

'adhesions are readily broken and the impreg nated sleeving yields to easy removal 'from: the

mandrel. It is then dipped or otherwise, treated with varnish solution, and dried thoroughly. By slightly stretching the length of impregnated 1 sleeving the finished product is obtained and is usable as a foundation for subsequent dippings or applications of ordinaryinsulatingvarnish, the

number of coatings being dependent upon the character of workfor which it is intended to be used. Medium togood grades of ordinary insulating varnishes .have been foundto-producea impregnating medium if desired. r v

.For a better understanding of the-invention, reference is made at this time to Figs. 2,3 and 4 of the drawing. These figures are enlarged diagrammatic showings of the relation 0f yarn strands in' thebraided tubular stock, in the same length of stock as compressed on the mandrel and held by the impregnating and dipping solution 'and in, the impregnated sleeving as slightly stretched to less'than original length for receiving the additional varnish coatings. Attention is called to the fact'that the longitudinally compacted tubing has the threads thereof crossed more times per inchv than in the-original braiding and that this condition is retainedby the saturating varnish causing the finished sleeving and tubing to have considerable springiness and elasticity.

The varnished sleeving thus made is not at may be. collapsed, folded double and compressed without materially injuring .the insulating qualities thereof. The varnished sleeving or tubing can be subjected to such abuses as combined twisting and stretching and will resume its originalhollow tubular shape ofit'sown accord. Referring now to the drawing, the bralded fabric 6 isshown' in Fig. 1 enveloping mandrel rod 1 and is securely clamped thereto near theends of the. rod by having cords 8 bound tightly around it Fig. 2 shows in further exaggerated proportion a simplified enlargement of a longitudinal section of the fabric'ii where the strands "of the. weave are somewhat widelyseparated and have I relatively few crossings. to

the inch. i Fig. 3 shows in a similar manner the sam amountgofsleeving as compacted on the mandrel and during the initial varnish applications. The sleeving is takenfrom the mandrel in this condition and further coated and dried. Thereafter the, sleeving is pulled out or stretched to somewhat less than original. length and thereafter any, further desired applications of varnishmay be added to secure the necessarywali thickness.

' Fig. 4 shows the relative condition of the yarn strands in the finished sleeving and tubing and in itself. an improved article of superior varnished sleeving and/or tubing and, so

they may be used advantageously as the initial .xinsulating. varnishes of their indicates clearly that the strands iii are held closer than in the initial braided material.

, Referring to Fig. 1 it will be appreciated that the compacted tubing will tend to stand out from the mandrel and that adhesions of sizing material will be particularly at the relatively small points of contact with the mandrel. These are easily broken looseby rubbing over the tubing when the impregnated material is dry. If the tubular braid on the mandrel isnot thus compressed, the adhesion of the sizing material, particularly in the case of varnishes, shell'acs, etc., is so continuous and so excessive that it becomes necessary to injure varnish and fabric before it canbe released from the mandrel. In many of such cases it is impossible to remove a usable section of impregnated sleeving from the mandrel As: shown in Fig. 5'the complete 'impregnated sleeving shown at H is provided with one or a plurality of varnishcoatings l2 thereby providing the improved varnished tubing or sleeving of the invention.

The impregnatedsleeving of id as such to users 'whoma'y choose toapply own specification thereto. It will be noted that it is not necessary the invention commerce to be to use the mandrels after the initial'impregnation has been effected. I

The "amount of slack'sleeving to be distributed over the mandrel maybe varied, especially as the yarn strand size and quality in the sleeving is varied. Heavier yarn strand 3| normally indicates a smaller excess length of sleeving.

What is claimedis: I v

1. The method oi making im'pregnatedsleeving comprising the steps or cutting tubular braided fabric into lengths in excess of the length of .mandrel rod, then inserting the rod into the tubing, longitudinally compacting substantially the entire length of tubing onto'the rod, securing the tubing to the rod adjacent each end, then distributing the compacted excess lengthjoi tubing evenly over the mandrel-rod betweenthe secured portions, applying impregnating material to the fabric in the-compacted conditionand allowing same to dry, then removing the securing means, then breaking down the'adhesion'of impregnatedxmaterlal on the mandrelrod, then removing the tubing from the rod.

2. The method of'making impregnated sleeving comprising the steps of enveloping a cylindrical mandrel rod with a length of tubular. braided frabric greater than by longitudinally compacting the braided fabric, then securing the .fabric to the rod adjacent the ends thereof, impregnating the fabric while an:

der compressive strain, and drying it, then-releasing the securing means, and removing the impregnated sleeving from the rod. i

3. The method of making impregnated sleeving which comprises the steps of compacting alength of tubular fabric onto amandrelrod of lesser length, securing the fabric near'the endsof the? in compressed condition, then subjecting the fabric to anfimpregnating.

mandrel to retain it medium, and drying it, submitting theimpreg nated fabric on the mandrelto frictionalpres sure to release adhering impregnating material from the mandrel, then'releasing the securing means. Y i e WILLIAM H. PEARCE.

thele'ngth of the rod there-I 

